Preparation method of polysaccharide fiber

ABSTRACT

A preparation method of a polysaccharide fiber is provided. The method includes the following steps. First, a polysaccharide material is provided. Next, the polysaccharide material is mixed with an ionic liquid to form a polysaccharide solution. Then, the polysaccharide solution is mixed with a forming liquid to form a formed polysaccharide article. Next, a homogenization treatment is performed on the formed polysaccharide article to form a homogeneous polysaccharide article. Then, the homogeneous polysaccharide article is dried to form a polysaccharide fiber.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 103126370, filed on Aug. 1, 2014. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The technical field relates to a preparation method of a polysaccharide fiber, and more particularly, to a preparation method of a regenerative polysaccharide fiber.

BACKGROUND

In recent years, scientists have been actively developing a regenerative fiber by dissolving an existing polymer material to replace the consumption of natural fiber. The regenerative fiber can be widely applied in various industries such as home decoration textiles, optical thin films, flexible electronic displays, cosmetics, medical drugs, and food additives. In the manufacture of a regenerative fiber, various chemical or physical methods are generally used to make the regenerative fiber have various different functions so as to meet the needs of the market, such as breathability, good hygroscopicity, easy to dye, antistatic, and anti-bacteria.

In the textile industry, the treatment of cotton waste products is a research focus. Since a cellulose fiber has both softness and hygroscopicity, the cellulose fiber is very suitable as a raw material of non-woven fabric. The current cellulose non-woven fabric adopts N-methylmorpholine N-oxide (NMMO) as the solvent of the cellulose. However, dissolving cellulose via NMMO not only requires high temperature, but also requires a complex forming process, thus increasing preparation costs thereof. Therefore, a preparation method of a regenerative fiber that can be performed under room temperature and having a simple process is urgently needed.

SUMMARY

The disclosure provides a preparation method of a polysaccharide fiber having the advantage of a simple process.

The disclosure provides a preparation method of a polysaccharide fiber including the following steps. First, a polysaccharide material is provided. Next, the polysaccharide material is mixed with an ionic liquid to form a polysaccharide solution. Then, the polysaccharide solution is mixed with a forming liquid to form a formed polysaccharide article. Next, a homogenization treatment is performed on the formed polysaccharide article to form a homogeneous polysaccharide article. Then, the homogeneous polysaccharide article is dried to form a polysaccharide fiber.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the polysaccharide material and the ionic liquid are mixed under room temperature to form the polysaccharide solution.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the homogenization treatment is performed via a high-speed stirring homogenizer to form the homogeneous polysaccharide article, and after the homogeneous polysaccharide article is dried, the formed polysaccharide fiber has a non-woven pattern.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the homogenization treatment step is performed via an emulsification homogenizer to form the homogeneous polysaccharide article, and after the homogeneous polysaccharide article is dried, the formed polysaccharide fiber has a thin film pattern.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the polysaccharide material includes a cellulose-containing material, a chitin-containing material, or a starch-containing material.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the cellulose-containing material includes wood pulp, bamboo, hemp, rice straw, coir, sugar cane, or a cotton product.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the chitin-containing material includes shrimp shell, crab shell, insect carapace, or squid cartilage.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the starch-containing material includes seed, tubers, or tuber of a plant.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the ionic liquid is composed of a cation and an anion. The cation includes a structure shown in formula (1):

-   -   wherein R₁ to R₅ are H or C₁ to C₈ hydrocarbon groups; the anion         is one selected from Cl⁻, Br⁻, I⁻, CH₃COO⁻, HCOO⁻, and PO₄ ³⁻.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the ionic liquid includes 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc).

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the forming liquid includes a first solvent and a second solvent. The first solvent includes water, methanol, ethanol, acetone, or a combination thereof. The second solvent includes an ionic liquid, dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), or a combination thereof.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the average fiber diameter of the polysaccharide fiber having a non-woven pattern is 13 μm to 30 μm.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the average fiber diameter of the polysaccharide fiber having a thin film pattern is 0.080 μm to 0.200 μm.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the mixing of the polysaccharide material with the ionic liquid further includes heating to 60° C. to 80° C.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the homogenization treatment is 3 minutes to 5 minutes.

In an embodiment of the disclosure, in the preparation method of a polysaccharide fiber, the polysaccharide material further includes a reactive dye, and after the polysaccharide solution is mixed with the forming liquid, the reactive dye and the polysaccharide material are separated to form the formed polysaccharide article without the reactive dye.

Based on the above, in the preparation method of a polysaccharide fiber provided in the embodiments of the disclosure, an ionic liquid in liquid state under room temperature is used. Therefore, the polysaccharide material and the ionic liquid can be mixed under room temperature to increase process convenience. Moreover, if needed, different homogenization treatments can be performed on the formed polysaccharide article to obtain a polysaccharide fiber having a non-woven pattern or a thin film pattern. Moreover, in the preparation method of a polysaccharide fiber of the embodiments of the disclosure, the reactive dye and the polysaccharide material can further be separated, and a decolored regenerative polysaccharide fiber can be obtained without a centrifugation treatment.

Several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a flow chart of a preparation method of a polysaccharide fiber according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1 is a flow chart of a preparation method of a polysaccharide fiber according to an embodiment of the disclosure. Referring to FIG. 1, first, step S100 is performed, in which a polysaccharide material is provided. In the present embodiment, the polysaccharide material is, for instance, a cellulose-containing material, a chitin-containing material, or a starch-containing material. Among these, cellulose is the most naturally abundant. The cellulose-containing material is, for instance, wood pulp, bamboo, hemp, rice straw, coir, sugar cane, or a cotton product. The chitin-containing material is, for instance, shrimp shell, crab shell, insect carapace, or squid cartilage. Chitin is a natural polymer material second only to cellulose in natural abundance, and chitin has good biocompatibility, hygroscopicity, and further has excellent functions such as anti-bacteria and anti-odor. The starch-containing material is, for instance, seed, tubers, or tuber of a plant, but the disclosure is not limited thereto.

In the present embodiment, the polysaccharide material can be miniaturized via a physical force, and the physical force is, for instance, a method such as crushing or grinding, but the disclosure is not limited thereto. In general, the molecular structure of the polysaccharide material has a plurality of hydrogen bond donors and hydrogen bond acceptors. For instance, in the polysaccharide material of the present embodiment, the hydrogen bond donors are hydrogen atoms in a hydroxyl group, and the hydrogen bond acceptors are oxygen atoms in a hydroxyl group. In this way, not only are hydrogen bonds abundant inside molecules of the polysaccharide material such that the polysaccharide material has a certain degree of intermolecular polarity, hydrogen bonds are also readily generated between molecules of the polysaccharide material. As a result, the polysaccharide material is not readily dissolved in a conventional solvent (such as water and most organic solvents).

In the present embodiment, referring to step S200 of FIG. 1, the polysaccharide material is mixed with an ionic liquid to form a polysaccharide solution. Specifically, the cation and the anion in the ionic liquid can interact with the oxygen atoms and the hydrogen atoms in the polysaccharide material, and therefore the hydrogen bonds between polysaccharide material molecules can be damaged, and the polysaccharide material can be sufficiently dissolved as a result to form the polysaccharide solution. In the present embodiment, the polysaccharide solution is a clear solution, but the disclosure is not limited thereto.

In the present embodiment, the ionic liquid is composed of a cation and an anion. The cation can include a structure shown in formula (1):

In the present embodiment, R₁ to R₅ can be H or C₁ to C₈ hydrocarbon groups. In the present embodiment, the anion can be one selected from Cl⁻, Br⁻, I⁻, CH₃COO⁻, HCOO⁻, and PO₄ ³⁻.

In an embodiment, the ionic liquid is, for instance, 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), and the structure thereof is as shown in formula (2) below.

It should be mentioned that, in comparison to an ionic liquid for which the anion is another type (such as Cl⁻), the ionic liquid for which the anion is CH₃COO⁻ (such as the above [EMIM]OAc) can dissolve the same amount of the polysaccharide material under a lower temperature. As a result, the energy used in the dissolution can be reduced.

It should be mentioned that, the ionic liquid is still in liquid state under room temperature. Therefore, the polysaccharide material and the ionic liquid can be directly mixed under room temperature. However, in other embodiments, the dissolution rate of the polysaccharide material can also be increased in step S200 via a heating method. The heating temperature is, for instance, 60° C. to 80° C., but the disclosure is not limited thereto.

Referring to step S300 of FIG. 1, the polysaccharide solution and the forming liquid are mixed to form a formed polysaccharide article. In the present embodiment, the forming liquid can include a first solvent and a second solvent. The first solvent is, for instance, water, methanol, ethanol, acetone, or a combination thereof. The second solvent is, for instance, any of the ionic liquids above, dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), or a combination thereof, but the disclosure is not limited thereto.

It should be mentioned that, the first solvent (such as water) and the second solvent (such as an ionic liquid) are filled between the molecules of the formed polysaccharide article formed after step S300. Therefore, after step S300, the formed polysaccharide article is gelatinous and does not yet have enough time to form a crystal, such that the intermolecular force thereof is weaker.

Next, referring to step S400 of FIG. 1, a homogenization treatment is performed on the formed polysaccharide article to form a homogeneous polysaccharide article. Since the formed polysaccharide article does not yet form a crystal, the formed polysaccharide article can be readily homogenized via physical force, and the physical force is, for instance, stirring or ultrasonic oscillation. The time of the homogenization treatment is, for instance, 3 minutes to 5 minutes, but the disclosure is not limited thereto. Then, referring to step S500 of FIG. 1, the homogeneous polysaccharide article is dried to form the polysaccharide fiber. In the present embodiment, the drying method includes, for instance, first performing suction filtration on the homogeneous polysaccharide article, and then drying the homogeneous polysaccharide article in shade for 24 hours, but the disclosure is not limited thereto.

It should be mentioned that, in the present embodiment, different homogenization treatment methods can be selected as needed. For instance, the formed polysaccharide article can be treated via a high-speed stirring homogenizer to form the homogeneous polysaccharide article. Then, after the homogeneous polysaccharide article is dried, a polysaccharide fiber having a non-woven pattern can be fan red. The average fiber diameter of the polysaccharide fiber having a non-woven pattern can be 13 μm to 30 μm. In an embodiment, the average fiber diameter of the polysaccharide fiber is 15 μm, but the disclosure is not limited thereto. Alternatively, the formed polysaccharide article can be treated via an emulsification homogenizer to form the homogeneous polysaccharide article. Then, after the homogeneous polysaccharide article is dried and compression molding is performed thereon, a polysaccharide fiber having a translucent thin film pattern can be formed. The average fiber diameter of the polysaccharide fiber having a thin film pattern can be 0.080 μm to 0.200 μm.

After all of steps S100 to S500 are performed, the preparation of the polysaccharide fiber of the present embodiment can be completed.

It should be mentioned that, in an embodiment, the polysaccharide material can further include a reactive dye. The reactive dye is formed by a dye precursor and a linking group, and the reactive dye can form a chemical bond with a plurality of functional groups of the polysaccharide material. The dye precursor of the reactive dye used in the polysaccharide material is, for instance, azo, anthraquinone, or phthalocyanine. The linking group of the reactive dye is, for instance, triazine, divinyl sulfone, quinoxaline, or pyrimidine. In the preparation method of a polysaccharide fiber of an embodiment of the disclosure, after the polysaccharide solution containing the reactive dye and the forming liquid are mixed, the reactive dye and the polysaccharide material can be separated such that the reactive dye enters the first solvent to form a decolored formed polysaccharide article.

In the following, the preparation and the characteristics of the polysaccharide fiber provided in the embodiments are described in detail via a number of experimental examples. However, the following experimental examples are not intended to limit the disclosure.

[Preparation of Polysaccharide Fiber]

To prove the preparation method of a polysaccharide fiber of the disclosure can prepare a polysaccharide fiber and the process is simple, a plurality of examples are provided below.

Example 1

First, wood pulp or a cotton product is crushed. Then, under 60° C. to 80° C., 5 wt % to 10 wt % of cellulose mucus was prepared by using [EMIM]OAc as the solvent. Then, 20 g of the cellulose mucus was poured or squeezed into 1 L of water to form a formed cellulose article. Then, a homogenization treatment was performed on the formed cellulose article for 3 minutes to 5 minutes at a rotational speed of 10000 rpm to 26000 rpm via a high-speed stirring homogenizer to form a homogeneous cellulose article. Lastly, after suction filtration was performed on the homogeneous cellulose article, the homogeneous cellulose article was dried in shade for 24 hours to obtain a cellulose non-woven fabric. The average fiber diameter of the cellulose non-woven fabric was 15 μm.

Example 2

First, 1 g of black and white newspaper was cut into a size of 2 cm×2 cm, and the newspaper was immersed in an aqueous solution of 1% sodium hydroxide for 1 hour to remove the ink. Then, after dissolution was performed under 80° C. for 4 hours by using 20 g of [EMIM]OAc, cellulose mucus was obtained. Then, the cellulose mucus was poured into a high-speed stirring homogenizer, and a homogenization treatment was performed at a rotational speed of 10000 rpm to 26000 rpm for 5 minutes. Lastly, after suction filtration and drying in shade for 24 hours, a cellulose non-woven fabric was obtained. The average fiber diameter of the cellulose non-woven fabric was 20 μm.

Example 3

First, 1 g of chitin powder was prepared. Then, after dissolution was performed under 80° C. for 8 hours by using 20 g of [EMIM]OAc, chitin mucus was obtained. Then, the chitin mucus was poured into a high-speed stirring homogenizer, and a homogenization treatment was performed at a rotational speed of 10000 rpm to 26000 rpm for 5 minutes. Lastly, after suction filtration and drying in shade for 24 hours, a chitin non-woven fabric was obtained. The average fiber diameter of the chitin non-woven fabric was 30 μm.

[Measurement of Degree of Polymerization]

Wood pulp board and pure cotton dyed fiber fabric containing 5 wt % of cellulose were dissolved respectively via NMMO and [EMIM]OAc. The dissolution temperature was 80° C.; the dissolution time was 8 hours. The degree of polymerization thereof was calculated according to the following equation: degree of polymerization=(total molecular weight)/(1 unit of molecular weight)×100%. Moreover, the retention rates of the wood pulp board and the pure cotton dyed fiber fabric after dissolution were calculated based on the degrees of polymerization of the wood pulp board and the pure cotton dyed fiber fabric before dissolution. In other words, the retention rates thereof were calculated based on 100% retention rates of the wood pulp board and the pure cotton dyed fiber fabric before dissolution according to the following equation: retention rate=(degree of polymerization of polysaccharide material before dissolution)/(degree of polymerization of polysaccharide material after dissolution)×100%. The results thereof are shown in Table 1 below.

TABLE 1 Degree of Polysaccharide material Solvent polymerization Retention rate Wood pulp board — 798 100% Pure cotton dyed fiber — 1451 100% fabric Wood pulp board NMMO 248 31% Pure cotton dyed fiber NMMO 453 32% fabric Wood pulp board [EMIM]OAc 619 78% Pure cotton dyed fiber [EMIM]OAc 1161 80% fabric

It should be mentioned that, a greater degree of polymerization after the dissolution of the polysaccharide material represents the structure of the polysaccharide material can be better retained in the solvent, that is, the retention rate is greater. It can be known from the results of Table 1 that, under the same dissolution temperature and dissolution time, by using [EMIM]OAc as the solvent, the extend of damage of the cellulose is less than that of NMMO. Specifically, the retention rate of the former can reach at least twice the retention rate of the latter. Therefore, in the industrial process in which cellulose is dissolved via NMMO, a protective agent is generally further added to prevent cellulose degradation. In the preparation method of a polysaccharide fiber of the disclosure, by treating cellulose with an ionic liquid, the degree of cellulose degradation can be significantly reduced in comparison to the degree of cellulose degradation for which NMMO is used. As a result, an additional protective agent is not needed.

[Measurement of Water Absorption Ratio]

In the following, some experimental examples are provided to compare the water absorption ratio of the cellulose non-woven fabric obtained via the preparation method of a polysaccharide fiber of the disclosure with the water absorption ratio of a commercial non-woven fabric. The detailed steps of the measurement of water absorption ratio are as follows. First, a weight T (g) of an empty tea bag was weighed, and the weighed empty tea bag was used as a tool for containing a sample. Then, a weight S (g) of a sample shown in Table 2 was weighed, and the weighed sample was placed inside the tea bag. Then, the tea bag containing the sample was immersed in distilled water for 5 minutes and then picked up and suspended for 5 minutes. After excess water was removed via dripping, a total weight W (g) of the tea bag and the sample after water absorption was weighed. The water absorption ratio was calculated according to the following equation: water absorption ratio=(W−(T+S)−T×W₀)/S, wherein W₀(g) is the water absorption amount of 1 g of tea bag. The calculation results thereof are listed in Table 2.

TABLE 2 Water absorption Polysaccharide fiber Solvent ratio Comparative Commercial PP — 1.78 example 1 non-woven fabric Comparative Wood pulp cellulose NMMO 3.73 example 2 non-woven fabric Experimental Wood pulp cellulose [EMIM]OAc 3.85 Example 1 non-woven fabric Experimental Cotton product cellulose [EMIM]OAc 3.78 Example 2 non-woven fabric

Comparative example 1 is a general commercial polypropene (PP) non-woven fabric, comparative example 2 is a wood pulp cellulose non-woven fabric obtained by using NMMO as the solvent, experimental example 1 is a wood pulp cellulose non-woven fabric obtained by using [EMIM]OAc as the solvent, and experimental example 2 is a cotton product cellulose non-woven fabric obtained by using [EMIM]OAc as the solvent. It can be known from the results of Table 2 that, the water absorption ratio of the regenerative fiber non-woven fabric made by [EMIM]OAc is superior to that of the current commercial PP non-woven fabric (greater by about two magnitudes). Moreover, the water absorption ratio of the regenerative fiber non-woven fabric made by [EMIM]OAc is similar to that of the cellulose non-woven fabric for which NMMO is currently used as the solvent.

It should be mentioned that, via visual observation, in experimental example 2, the cotton fiber dyed by the reactive dyes (azo and triazine) dissolved via [EMIM]OAc can facilitate decolorization of the cotton fiber, and white regenerative cellulose fiber can be obtained as a result. On the contrary, by dissolving the cotton fiber dyed by the reactive dyes via NMMO, a pink regenerative cellulose fiber is obtained.

Based on the above, in the preparation method of a polysaccharide fiber provided in the embodiments of the disclosure, an ionic liquid in liquid state under room temperature is used. Therefore, the polysaccharide material and the ionic liquid can be mixed under room temperature to increase process convenience. Moreover, by using the ionic liquid as the solvent, the structure of the polysaccharide material can retain good retention rate. If needed, different homogenization treatments can also be performed on the formed polysaccharide article to obtain a regenerative polysaccharide fiber having a non-woven pattern or a thin film pattern, and the regenerative polysaccharide fiber having a non-woven pattern can have superior water absorption ratio to the commercial PP non-woven fabric. Moreover, in the preparation method of a polysaccharide fiber of the embodiments of the disclosure, the reactive dye and the polysaccharide material can further be separated, and a decolored regenerative polysaccharide fiber can be obtained without a centrifugation treatment.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A preparation method of a polysaccharide fiber, comprising: providing a polysaccharide material; mixing the polysaccharide material with an ionic liquid to form a polysaccharide solution; mixing the polysaccharide solution with a forming liquid to form a formed polysaccharide article; performing a homogenization treatment on the formed polysaccharide article to form a homogeneous polysaccharide article; and drying the homogeneous polysaccharide article to form the polysaccharide fiber.
 2. The method of claim 1, wherein the polysaccharide material and the ionic liquid are mixed under room temperature to form the polysaccharide solution.
 3. The method of claim 1, wherein the homogenization treatment is performed via a high-speed stirring homogenizer to form the homogeneous polysaccharide article, and after the homogeneous polysaccharide article is dried, the formed polysaccharide fiber has a non-woven pattern.
 4. The method of claim 1, wherein the homogenization treatment is performed via an emulsification homogenizer to form the homogeneous polysaccharide article, and after the homogeneous polysaccharide article is dried, the formed polysaccharide fiber has a thin film pattern.
 5. The method of claim 1, wherein the polysaccharide material comprises a cellulose-containing material, a chitin-containing material, or a starch-containing material.
 6. The method of claim 5, wherein the cellulose-containing material comprises wood pulp, bamboo, hemp, rice straw, coir, sugar cane, or a cotton product.
 7. The method of claim 5, wherein the chitin-containing material comprises shrimp shell, crab shell, insect carapace, or squid cartilage.
 8. The method of claim 5, wherein the starch-containing material comprises seed, tubers, or tuber of a plant.
 9. The method of claim 1, wherein the ionic liquid is composed of a cation and an anion, and the cation comprises a structure shown in formula (1):

wherein R₁ to R₅ are H or C₁ to C₈ hydrocarbon groups; the anion is one selected from Cl⁻, Br⁻, CH₃COO⁻, HCOO⁻, and PO₄ ³⁻.
 10. The method of claim 9, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc).
 11. The method of claim 1, wherein the forming liquid comprises a first solvent and a second solvent, the first solvent comprises water, methanol, ethanol, acetone, or a combination thereof, and the second solvent comprises the ionic solution, dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), or a combination thereof.
 12. The method of claim 2, wherein an average fiber diameter of the polysaccharide fiber having a non-woven pattern is 13 μm to 30 μm.
 13. The method of claim 3, wherein an average fiber diameter of the polysaccharide fiber having a thin film pattern is 0.080 μm to 0.200 μm.
 14. The method of claim 1, wherein the mixing of the polysaccharide material with the ionic liquid further comprises heating to 60° C. to 80° C.
 15. The method of claim 1, wherein the homogenization treatment is 3 minutes to 5 minutes.
 16. The method of claim 1, wherein the polysaccharide material further comprises a reactive dye, and after the polysaccharide solution is mixed with the forming liquid, the reactive dye and the polysaccharide material are separated to form the formed polysaccharide article without the reactive dye. 